The migration of neutrophils (PMN), monocytes and lymphocytes to inflammatory sites in response to chemotactic factors is critical to host defense against bacteria and tumors. In PMN and monocytes, bactericidal and tumoricidal activity results from the production of toxic oxygen intermediates. Our previous studies showed that chemotactic factors prime PMN to produce excessive quantities of O2- upon stimulation with phorbol myristate acetate or opsonized zymosan particles. This priming provides a means of creating a more efficient killer cell while en route to an inflammation site. The specific aims are to determine the mechanism of chemotactic factor priming at the subcellular level and the events following chemotactic factor stimulation of PMN and monocytes, including the role of NADPH in supporting or terminating the production of O2- and chemiluminescence. We will utilize fluorescent C5a, casein and formylated peptides with a unique flow cytometry system to determine the coexistence of chemotactic factor receptors on single cells, the maturational development of PMN chemotactic receptors and the interrelationship and kinetics of chemotactic factor binding, oxidation of pyridine nucleotides, and membrane depolarization. Currently, very little is known about the interaction of chemotactic factor with human lymphocytes. Recently, we have developed a human lymphocyte chemotaxis assay in this laboratory and have discovered a chemotactic lymphokine produced by human T lymphocytes which attracts other T lymphocytes. We will characterize this lymphokine and determine its source and similarity to lymphokines chemotactic for monocytes and PMN, as well as its specificity for T cell subsets. Responses of T cell subsets to casein and C5a will also be compared. Finally, lymphocyte chemotaxis assays will be utilized to analyze lymphocyte responsiveness in malignancy when preliminary data indicate a depressed in vitro migration. The nature of this altered response and its relationship to malignancy and therapy will be addressed. In summary, the study will focus on the interrelationship of chemotactic factor responses and stimulation of toxic oxygen intermediate production by PMN and monocytes, as well as the potential mechanism by which lymphocytes are attracted to a site of antigenic challenge. Alteration of lymphocyte responses in patients with malignancy may represent another means by which tumor cells avert immune rejection.